Here, as a result of the formation of a first and a second forming section, between which an intermediate section is formed, the blind rivet can connect arrangements of at least two work-pieces with different thicknesses to one another (what is known as a multiple-region rivet or a rivet with variable grip).
Here, different requirements exist which partially go against one another. Firstly, the range of the possible clamping thicknesses should be as large as possible. Furthermore, the radial widening of the rivet sleeve should be limited in the region of the workpieces. This is intended to avoid rivet-sleeve material being squeezed between the workpieces on account of great radial widening. Here, there is firstly the risk that the workpieces burst open. Furthermore, this can lead to leaks (blind rivets of the described type can optionally also achieve a sealing action with respect to fluids).
Furthermore, in some applications, the workpieces do not bear against one another in an initial state. In this case, it should be ensured during the forming of the rivet sleeve that the workpieces are first of all drawn towards one another (“tightened”) before the setting operation is ended (the pin tears off at a predetermined break point which is provided as a rule).
An improved drawing or tightening behaviour of this type can optionally also avoid an operating person of a blind-rivet tool having to exert a prestressing force on the workpiece arrangement before the setting operation.
Document WO 2009/098431 A1 discloses a blind rivet of this type with variable grip. Here, the pin head is configured to engage around the blind-side end of the sleeve shank. Furthermore, adjacently to the pin head, the pin has radial projections which engage behind deformed material of the rivet sleeve. This can prevent the residual pin accidentally being detached from the workpiece connection which is produced in this way, after setting and after tearing off at the predetermined break point.
A further blind rivet with variable grip is known from document EP 0 677 666 B1.
Against the above background, it is an object of the invention to specify an improved blind rivet and an improved workpiece arrangement.